1. Field of the Invention
The invention relates to a brushless DC motor, and more particularly to a universal brushless DC motor.
2. Description of the Related Art
Conventional brushless DC motors adopt a special integrated circuit as a drive circuit, and generally operate as an open loop system. In principle, they can be integrated with a control system of a device to be driven to form a closed loop system, but the high cost of development of such system is generally prohibitive. For example, a brushless DC motor developed for use in electric fans may be only slightly different in terms of control from a motor that would be otherwise fit to drive air conditioners; however, it may be less expensive to develop the latter from scratch rather than by converting the former.